| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing an exhaust pipe, which method can easily manufacture the exhaust pipe including a curved dual pipe structure. SOLUTION: High pressure fluid is jetted from a high pressure fluid jetting port 34. The high pressure fluid fills inside a second metallic pipe 12 and inside the rear half portion 18 of a first metallic pipe 11. Further, the high pressure fluid intrudes between the second metallic pipe 12 and the front half portion 17 of the first metallic pipe 11 via a small hole 13. As a result, the front half portion 17 of the first metallic pipe 11 begins to swell toward the recessed portions 26, 31 for forming the dual pipe. At the same time, the rear half portion 18 of the first metallic pipe 11 begins to swell toward the recessed portions 27, 32 for forming the large diameter portion. According to the present invention, straight materials can be bent. Further, the high pressure fluid is jetted between the first metallic pipe corresponding to an outer pipe and the second metallic pipe corresponding to an inner pipe. Then, the fist metallic pipe swells, and the dual pipe structure can be achieved, Thus, the exhaust pipe including the curved dual pipe structure can be easily manufactured. COPYRIGHT: (C)2009,JPO&INPIT |
